Error concealment method and apparatus of audio signals

摘要

An apparatus for concealing a frame or multiple of frames where errors have occurred in a digital audio signal which is subband coded and transform coded in units of an error-correctible frame is described. The error concealment apparatus includes an error detector (10) for receiving frequency coefficients representing the encoded digital audio signal and detecting whether an error has occurred for each frame, a decoder (100) for decoding the frequency coefficients by respective subbands forming a frequency domain of the whole audio signal with respect to the input frequency coefficients, a buffer (70) for storing the frequency coefficients decoded by said decoder (100), a frequency coefficient reconstruction portion (60) for reconstructing the frequency coefficients of a frame or multiple of frames where errors have occurred using predetermined weight values and frequency coefficient(s) of subband adjacent to the error frame(s) among the frequency coefficients belonging to a frame which is stored in the buffer (70) and is adjacent to the error frame(s), and updating the frequency coefficients of the error frame(s), and storing the frequency coefficients in the buffer (70), in response to the error detection result from error detector (10) and a synthesis filter bank (80) for receiving the frequency coefficients stored in the buffer (70) and converting the frequency coefficients into an audio signal of a time domain, in the same sequence as a decoding sequence.